support for @ shortcut. (#450)

Author: Byron

git-refspec/src/parse.rs

@@ -50,7 +50,7 @@ pub(crate) mod function {
             }
         };
 
-        let (src, dst) = match spec.find_byte(b':') {
+        let (mut src, dst) = match spec.find_byte(b':') {
             Some(pos) => {
                 let (src, dst) = spec.split_at(pos);
                 let dst = &dst[1..];
@@ -86,6 +86,11 @@ pub(crate) mod function {
             }
         };
 
+        if let Some(spec) = src.as_mut() {
+            if *spec == "@" {
+                *spec = "HEAD".into();
+            }
+        }
         let (src, src_had_pattern) = validated(src, operation == Operation::Push)?;
         let (dst, dst_had_pattern) = validated(dst, false)?;
         if mode != Mode::Negative && src_had_pattern != dst_had_pattern {
@@ -103,10 +108,11 @@ pub(crate) mod function {
         match spec {
             Some(spec) => {
                 let glob_count = spec.iter().filter(|b| **b == b'*').take(2).count();
-                if glob_count == 2 {
+                if glob_count > 1 {
                     return Err(Error::PatternUnsupported { pattern: spec.into() });
                 }
-                if glob_count == 1 {
+                let has_globs = glob_count == 1;
+                if has_globs {
                     let mut buf = smallvec::SmallVec::<[u8; 256]>::with_capacity(spec.len());
                     buf.extend_from_slice(spec);
                     let glob_pos = buf.find_byte(b'*').expect("glob present");
@@ -132,7 +138,7 @@ pub(crate) mod function {
                             }
                         })?;
                 }
-                Ok((Some(spec), glob_count == 1))
+                Ok((Some(spec), has_globs))
             }
             None => Ok((None, false)),
         }

git-refspec/tests/fixtures/generated-archives/make_baseline.tar.xz

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:d68f02fcf17b72dfb953ab02f3d448d7b859d822aa71835856045a291a645d5a
-size 9344
+oid sha256:ace43ca904298dc76951863d41485ae0c21ee9b88abf7d604eb6c6e7efa18ab2
+size 9352

git-refspec/tests/fixtures/make_baseline.sh

@@ -80,6 +80,12 @@ baseline fetch 'HEAD'
 baseline push '@'
 baseline fetch '@'
 
+baseline push '^@'
+baseline fetch '^@'
+
+baseline push '+@'
+baseline fetch '+@'
+
 baseline fetch 'HEAD:'
 
 baseline push ':refs/remotes/frotz/deleteme'

git-refspec/tests/parse/fetch.rs

@@ -7,6 +7,13 @@ fn exclude() {
     assert_parse("^a*", Instruction::Fetch(Fetch::Exclude { src: b("a*") }));
 }
 
+#[test]
+fn ampersand_is_resolved_to_head() {
+    assert_parse("@", Instruction::Fetch(Fetch::Only { src: b("HEAD") }));
+    assert_parse("+@", Instruction::Fetch(Fetch::Only { src: b("HEAD") }));
+    assert_parse("^@", Instruction::Fetch(Fetch::Exclude { src: b("HEAD") }));
+}
+
 #[test]
 fn lhs_colon_empty_fetches_only() {
     assert_parse("src:", Instruction::Fetch(Fetch::Only { src: b("src") }));

git-refspec/tests/parse/push.rs

@@ -7,6 +7,28 @@ fn exclude() {
     assert_parse("^a*", Instruction::Push(Push::Exclude { src: b("a*") }));
 }
 
+#[test]
+fn ampersand_is_resolved_to_head() {
+    assert_parse(
+        "@",
+        Instruction::Push(Push::Matching {
+            src: b("HEAD"),
+            dst: b("HEAD"),
+            allow_non_fast_forward: false,
+        }),
+    );
+
+    assert_parse(
+        "+@",
+        Instruction::Push(Push::Matching {
+            src: b("HEAD"),
+            dst: b("HEAD"),
+            allow_non_fast_forward: true,
+        }),
+    );
+    assert_parse("^@", Instruction::Push(Push::Exclude { src: b("HEAD") }));
+}
+
 #[test]
 fn lhs_colon_rhs_pushes_single_ref() {
     assert_parse(